Seeing Is Believing: IEC-HS after CAR T Cells.

Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) is a complication seen in patients receiving chimeric antigen receptor (CAR) T cells, more frequently in those with CD22- or BCMA-targeted constructs compared with CD19. While associated with higher CAR T-cell expansion and a unique cytokine profile, the constellation of three cytokines (IFNγ, IL10, and IL1RA) correlated most strongly with IEC-HS severity and may help guide preemptive interventions. See related article by Srinagesh et al., p. 225.